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Karginov TA, Ménoret A, Leclair NK, Harrison AG, Chandiran K, Suarez-Ramirez JE, Yurieva M, Karlinsey K, Wang P, O'Neill RJ, Murphy PA, Adler AJ, Cauley LS, Anczuków O, Zhou B, Vella AT. Autoregulated splicing of TRA2β programs T cell fate in response to antigen-receptor stimulation. Science 2024; 385:eadj1979. [PMID: 39265028 DOI: 10.1126/science.adj1979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 03/13/2024] [Accepted: 07/09/2024] [Indexed: 09/14/2024]
Abstract
T cell receptor (TCR) sensitivity to peptide-major histocompatibility complex (MHC) dictates T cell fate. Canonical models of TCR sensitivity cannot be fully explained by transcriptional regulation. In this work, we identify a posttranscriptional regulatory mechanism of TCR sensitivity that guides alternative splicing of TCR signaling transcripts through an evolutionarily ultraconserved poison exon (PE) in the RNA-binding protein (RBP) TRA2β in mouse and human. TRA2β-PE splicing, seen during cancer and infection, was required for TCR-induced effector T cell expansion and function. Tra2β-PE skipping enhanced T cell response to antigen by increasing TCR sensitivity. As antigen levels decreased, Tra2β-PE reinclusion allowed T cell survival. Finally, we found that TRA2β-PE was first included in the genome of jawed vertebrates that were capable of TCR gene rearrangements. We propose that TRA2β-PE splicing acts as a gatekeeper of TCR sensitivity to shape T cell fate.
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Affiliation(s)
- Timofey A Karginov
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Antoine Ménoret
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Nathan K Leclair
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06030, USA
| | - Andrew G Harrison
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Karthik Chandiran
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Jenny E Suarez-Ramirez
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Marina Yurieva
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06030, USA
| | - Keaton Karlinsey
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Penghua Wang
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Rachel J O'Neill
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Patrick A Murphy
- Center for Vascular Biology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Adam J Adler
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Linda S Cauley
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
| | - Olga Anczuków
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Beiyan Zhou
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Anthony T Vella
- Department of Immunology, School of Medicine, University of Connecticut, UConn Health, Farmington, CT 06030, USA
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2
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Kim YJ, Nomakuchi T, Papaleonidopoulou F, Yang L, Zhang Q, Krainer AR. Gene-specific nonsense-mediated mRNA decay targeting for cystic fibrosis therapy. Nat Commun 2022; 13:2978. [PMID: 35624092 PMCID: PMC9142507 DOI: 10.1038/s41467-022-30668-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 05/06/2022] [Indexed: 12/20/2022] Open
Abstract
Low CFTR mRNA expression due to nonsense-mediated mRNA decay (NMD) is a major hurdle in developing a therapy for cystic fibrosis (CF) caused by the W1282X mutation in the CFTR gene. CFTR-W1282X truncated protein retains partial function, so increasing its levels by inhibiting NMD of its mRNA will likely be beneficial. Because NMD regulates the normal expression of many genes, gene-specific stabilization of CFTR-W1282X mRNA expression is more desirable than general NMD inhibition. Synthetic antisense oligonucleotides (ASOs) designed to prevent binding of exon junction complexes (EJC) downstream of premature termination codons (PTCs) attenuate NMD in a gene-specific manner. We describe cocktails of three ASOs that specifically increase the expression of CFTR-W1282X mRNA and CFTR protein upon delivery into human bronchial epithelial cells. This treatment increases the CFTR-mediated chloride current. These results set the stage for clinical development of an allele-specific therapy for CF caused by the W1282X mutation. The W1282X nonsense mutation in the CFTR gene causes cystic fibrosis by reducing its mRNA and functional protein levels. Here the authors developed antisense-oligonucleotide cocktails that restore CFTR protein function by gene-specific stabilization of CFTR mRNA.
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Affiliation(s)
- Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Tomoki Nomakuchi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA.,Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Foteini Papaleonidopoulou
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Francis Crick Institute, London, 1140062, UK
| | - Lucia Yang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Genetics, Stony Brook University, Stony Brook, NY, 11794, USA.,Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY, 11794, USA
| | - Qian Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,Graduate Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
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3
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Kim YJ, Sivetz N, Layne J, Voss DM, Yang L, Zhang Q, Krainer AR. Exon-skipping antisense oligonucleotides for cystic fibrosis therapy. Proc Natl Acad Sci U S A 2022; 119:e2114858118. [PMID: 35017301 PMCID: PMC8784140 DOI: 10.1073/pnas.2114858118] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/16/2021] [Indexed: 11/25/2022] Open
Abstract
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), and the CFTR-W1282X nonsense mutation causes a severe form of CF. Although Trikafta and other CFTR-modulation therapies benefit most CF patients, targeted therapy for patients with the W1282X mutation is lacking. The CFTR-W1282X protein has residual activity but is expressed at a very low level due to nonsense-mediated messenger RNA (mRNA) decay (NMD). NMD-suppression therapy and read-through therapy are actively being researched for CFTR nonsense mutants. NMD suppression could increase the mutant CFTR mRNA, and read-through therapies may increase the levels of full-length CFTR protein. However, these approaches have limitations and potential side effects: because the NMD machinery also regulates the expression of many normal mRNAs, broad inhibition of the pathway is not desirable, and read-through drugs are inefficient partly because the mutant mRNA template is subject to NMD. To bypass these issues, we pursued an exon-skipping antisense oligonucleotide (ASO) strategy to achieve gene-specific NMD evasion. A cocktail of two splice-site-targeting ASOs induced the expression of CFTR mRNA without the premature-termination-codon-containing exon 23 (CFTR-Δex23), which is an in-frame exon. Treatment of human bronchial epithelial cells with this cocktail of ASOs that target the splice sites flanking exon 23 results in efficient skipping of exon 23 and an increase in CFTR-Δex23 protein. The splice-switching ASO cocktail increases the CFTR-mediated chloride current in human bronchial epithelial cells. Our results set the stage for developing an allele-specific therapy for CF caused by the W1282X mutation.
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Affiliation(s)
- Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY 11794
- Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY 11794
| | - Nicole Sivetz
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Jessica Layne
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Dillon M Voss
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY 11794
- Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY 11794
| | - Lucia Yang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- Graduate Program in Genetics, Stony Brook University, Stony Brook, NY 11794
- Medical Scientist Training Program, Stony Brook University School of Medicine, Stony Brook, NY 11794
| | - Qian Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- Graduate Program in Molecular and Cell Biology, Stony Brook University, Stony Brook, NY 11794
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4
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Flynn LL, Mitrpant C, Adams A, Pitout IL, Stirnweiss A, Fletcher S, Wilton SD. Targeted SMN Exon Skipping: A Useful Control to Assess In Vitro and In Vivo Splice-Switching Studies. Biomedicines 2021; 9:552. [PMID: 34069072 PMCID: PMC8156830 DOI: 10.3390/biomedicines9050552] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/11/2021] [Accepted: 05/11/2021] [Indexed: 01/23/2023] Open
Abstract
The literature surrounding the use of antisense oligonucleotides continues to grow, with new disease and mechanistic applications constantly evolving. Furthermore, the discovery and advancement of novel chemistries continues to improve antisense delivery, stability and effectiveness. For each new application, a rational sequence design is recommended for each oligomer, as is chemistry and delivery optimization. To confirm oligomer delivery and antisense activity, a positive control AO sequence with well characterized target-specific effects is recommended. Here, we describe splice-switching antisense oligomer sequences targeting the ubiquitously expressed human and mouse SMN and Smn genes for use as control AOs for this purpose. We report two AO sequences that induce targeted skipping of SMN1/SMN2 exon 7 and two sequences targeting the Smn gene, that induce skipping of exon 5 and exon 7. These antisense sequences proved effective in inducing alternative splicing in both in vitro and in vivo models and are therefore broadly applicable as controls. Not surprisingly, we discovered a number of differences in efficiency of exon removal between the two species, further highlighting the differences in splice regulation between species.
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Affiliation(s)
- Loren L. Flynn
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
- Black Swan Pharmaceuticals, Wake Forest, NC 27587, USA
| | - Chalermchai Mitrpant
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Abbie Adams
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
| | - Ianthe L. Pitout
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- PYC Therapeutics, Nedlands, WA 6009, Australia;
| | | | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
- PYC Therapeutics, Nedlands, WA 6009, Australia;
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia; (L.L.F.); (A.A.); (I.L.P.); (S.F.)
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia;
- Centre for Neuromuscular & Neurological Disorders, University of Western Australia, Crawley, WA 6009, Australia
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5
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Selective suppression of polyglutamine-expanded protein by lipid nanoparticle-delivered siRNA targeting CAG expansions in the mouse CNS. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 24:1-10. [PMID: 33738134 PMCID: PMC7937577 DOI: 10.1016/j.omtn.2021.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 02/09/2021] [Indexed: 12/11/2022]
Abstract
Polyglutamine (polyQ) diseases are inherited neurodegenerative disorders caused by expansion of cytosine-adenine-guanine (CAG)-trinucleotide repeats in causative genes. These diseases include spinal and bulbar muscular atrophy (SBMA), Huntington’s disease, dentatorubral-pallidoluysian atrophy, and spinocerebellar ataxias. Targeting expanded CAG repeats is a common therapeutic approach to polyQ diseases, but concomitant silencing of genes with normal CAG repeats may lead to toxicity. Previous studies have shown that CAG repeat-targeting small interfering RNA duplexes (CAG-siRNAs) have the potential to selectively suppress mutant proteins in in vitro cell models of polyQ diseases. However, in vivo application of these siRNAs has not yet been investigated. In this study, we demonstrate that an unlocked nucleic acid (UNA)-modified CAG-siRNA shows high selectivity for polyQ-expanded androgen receptor (AR) inhibition in in vitro cell models and that lipid nanoparticle (LNP)-mediated delivery of the CAG-siRNA selectively suppresses mutant AR in the central nervous system of an SBMA mouse model. In addition, a subcutaneous injection of the LNP-delivered CAG-siRNA efficiently suppresses mutant AR in the skeletal muscle of the SBMA mouse model. These results support the therapeutic potential of LNP-delivered UNA-modified CAG-siRNAs for selective suppression of mutant proteins in SBMA and other polyQ diseases.
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6
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Abstract
The genetic basis for most inherited neurodegenerative diseases has been identified, yet there are limited disease-modifying therapies for these patients. A new class of drugs-antisense oligonucleotides (ASOs)-show promise as a therapeutic platform for treating neurological diseases. ASOs are designed to bind to the RNAs either by promoting degradation of the targeted RNA or by elevating expression by RNA splicing. Intrathecal injection into the cerebral spinal fluid results in broad distribution of antisense drugs and long-term effects. Approval of nusinersen in 2016 demonstrated that effective treatments for neurodegenerative diseases can be identified and that treatments not only slow disease progression but also improve some symptoms. Antisense drugs are currently in development for amyotrophic lateral sclerosis, Huntington's disease, Alzheimer's disease, Parkinson's disease, and Angelman syndrome, and several drugs are in late-stage research for additional neurological diseases. This review highlights the advances in antisense technology as potential treatments for neurological diseases.
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Affiliation(s)
- C Frank Bennett
- Ionis Pharmaceuticals Inc., Carlsbad, California 92010, USA;
| | | | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA
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7
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Leclair NK, Brugiolo M, Urbanski L, Lawson SC, Thakar K, Yurieva M, George J, Hinson JT, Cheng A, Graveley BR, Anczuków O. Poison Exon Splicing Regulates a Coordinated Network of SR Protein Expression during Differentiation and Tumorigenesis. Mol Cell 2020; 80:648-665.e9. [PMID: 33176162 PMCID: PMC7680420 DOI: 10.1016/j.molcel.2020.10.019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/07/2020] [Accepted: 10/12/2020] [Indexed: 12/18/2022]
Abstract
The RNA isoform repertoire is regulated by splicing factor (SF) expression, and alterations in SF levels are associated with disease. SFs contain ultraconserved poison exon (PE) sequences that exhibit greater identity across species than nearby coding exons, but their physiological role and molecular regulation is incompletely understood. We show that PEs in serine-arginine-rich (SR) proteins, a family of 14 essential SFs, are differentially spliced during induced pluripotent stem cell (iPSC) differentiation and in tumors versus normal tissues. We uncover an extensive cross-regulatory network of SR proteins controlling their expression via alternative splicing coupled to nonsense-mediated decay. We define sequences that regulate PE inclusion and protein expression of the oncogenic SF TRA2β using an RNA-targeting CRISPR screen. We demonstrate location dependency of RS domain activity on regulation of TRA2β-PE using CRISPR artificial SFs. Finally, we develop splice-switching antisense oligonucleotides to reverse the increased skipping of TRA2β-PE detected in breast tumors, altering breast cancer cell viability, proliferation, and migration.
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Affiliation(s)
- Nathan K Leclair
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA; Graduate Program in Genetics and Development, UConn Health, Farmington, CT, USA
| | - Mattia Brugiolo
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Laura Urbanski
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA; Graduate Program in Genetics and Development, UConn Health, Farmington, CT, USA
| | - Shane C Lawson
- Graduate Program in Genetics and Development, UConn Health, Farmington, CT, USA; Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
| | - Ketan Thakar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Marina Yurieva
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Joshy George
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA; Institute for Systems Genomics, UConn Health, Farmington, CT, USA
| | - John Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA; Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
| | - Albert Cheng
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA; Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA; Institute for Systems Genomics, UConn Health, Farmington, CT, USA
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA; Institute for Systems Genomics, UConn Health, Farmington, CT, USA
| | - Olga Anczuków
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA; Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA; Institute for Systems Genomics, UConn Health, Farmington, CT, USA.
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8
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Simon CM, Van Alstyne M, Lotti F, Bianchetti E, Tisdale S, Watterson DM, Mentis GZ, Pellizzoni L. Stasimon Contributes to the Loss of Sensory Synapses and Motor Neuron Death in a Mouse Model of Spinal Muscular Atrophy. Cell Rep 2020; 29:3885-3901.e5. [PMID: 31851921 PMCID: PMC6956708 DOI: 10.1016/j.celrep.2019.11.058] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 10/08/2019] [Accepted: 11/14/2019] [Indexed: 12/31/2022] Open
Abstract
Reduced expression of the survival motor neuron (SMN) protein causes the neurodegenerative disease spinal muscular atrophy (SMA). Here, we show that adeno-associated virus serotype 9 (AAV9)-mediated delivery of Stasimon—a gene encoding an endoplasmic reticulum (ER)-resident transmembrane protein regulated by SMN—improves motor function in a mouse model of SMA through multiple mechanisms. In proprioceptive neurons, Stasimon overexpression prevents the loss of afferent synapses on motor neurons and enhances sensory-motor neurotransmission. In motor neurons, Stasimon suppresses neurodegeneration by reducing phosphorylation of the tumor suppressor p53. Moreover, Stasimon deficiency converges on SMA-related mechanisms of p53 upregulation to induce phosphorylation of p53 through activation of p38 mitogen-activated protein kinase (MAPK), and pharmacological inhibition of this kinase prevents motor neuron death in SMA mice. These findings identify Stasimon dysfunction induced by SMN deficiency as an upstream driver of distinct cellular cascades that lead to synaptic loss and motor neuron degeneration, revealing a dual contribution of Stasimon to motor circuit pathology in SMA. SMN deficiency causes motor circuit dysfunction in SMA. Simon et al. show that Stasimon—an ER-resident protein regulated by SMN—contributes to sensory synaptic loss and motor neuron death in SMA mice through distinct mechanisms. In motor neurons, Stasimon dysfunction induces p38 MAPK-mediated phosphorylation of p53 whose inhibition prevents neurodegeneration.
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Affiliation(s)
- Christian M Simon
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Meaghan Van Alstyne
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Elena Bianchetti
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Sarah Tisdale
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - D Martin Watterson
- Department of Pharmacology, Northwestern University, Chicago, IL 60611, USA
| | - George Z Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
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9
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Bennett CF, Krainer AR, Cleveland DW. Antisense Oligonucleotide Therapies for Neurodegenerative Diseases. Annu Rev Neurosci 2020; 42:385-406. [PMID: 31283897 DOI: 10.1146/annurev-neuro-070918-050501] [Citation(s) in RCA: 194] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Antisense oligonucleotides represent a novel therapeutic platform for the discovery of medicines that have the potential to treat most neurodegenerative diseases. Antisense drugs are currently in development for the treatment of amyotrophic lateral sclerosis, Huntington's disease, and Alzheimer's disease, and multiple research programs are underway for additional neurodegenerative diseases. One antisense drug, nusinersen, has been approved for the treatment of spinal muscular atrophy. Importantly, nusinersen improves disease symptoms when administered to symptomatic patients rather than just slowing the progression of the disease. In addition to the benefit to spinal muscular atrophy patients, there are discoveries from nusinersen that can be applied to other neurological diseases, including method of delivery, doses, tolerability of intrathecally delivered antisense drugs, and the biodistribution of intrathecal dosed antisense drugs. Based in part on the early success of nusinersen, antisense drugs hold great promise as a therapeutic platform for the treatment of neurological diseases.
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Affiliation(s)
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, California 92093, USA
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10
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Nusinersen ameliorates motor function and prevents motoneuron Cajal body disassembly and abnormal poly(A) RNA distribution in a SMA mouse model. Sci Rep 2020; 10:10738. [PMID: 32612161 PMCID: PMC7330045 DOI: 10.1038/s41598-020-67569-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/08/2020] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease characterized by degeneration of spinal cord alpha motor neurons (αMNs). SMA is caused by the homozygous deletion or mutation of the survival motor neuron 1 (SMN1) gene, resulting in reduced expression of SMN protein, which leads to αMN degeneration and muscle atrophy. The majority of transcripts of a second gene (SMN2) generate an alternative spliced isoform that lacks exon 7 and produces a truncated nonfunctional form of SMN. A major function of SMN is the biogenesis of spliceosomal snRNPs, which are essential components of the pre-mRNA splicing machinery, the spliceosome. In recent years, new potential therapies have been developed to increase SMN levels, including treatment with antisense oligonucleotides (ASOs). The ASO-nusinersen (Spinraza) promotes the inclusion of exon 7 in SMN2 transcripts and notably enhances the production of full-length SMN in mouse models of SMA. In this work, we used the intracerebroventricular injection of nusinersen in the SMN∆7 mouse model of SMA to evaluate the effects of this ASO on the behavior of Cajal bodies (CBs), nuclear structures involved in spliceosomal snRNP biogenesis, and the cellular distribution of polyadenylated mRNAs in αMNs. The administration of nusinersen at postnatal day (P) 1 normalized SMN expression in the spinal cord but not in skeletal muscle, rescued the growth curve and improved motor behavior at P12 (late symptomatic stage). Importantly, this ASO recovered the number of canonical CBs in MNs, significantly reduced the abnormal accumulation of polyadenylated RNAs in nuclear granules, and normalized the expression of the pre-mRNAs encoding chondrolectin and choline acetyltransferase, two key factors for αMN homeostasis. We propose that the splicing modulatory function of nusinersen in SMA αMN is mediated by the rescue of CB biogenesis, resulting in enhanced polyadenylated pre-mRNA transcription and splicing and nuclear export of mature mRNAs for translation. Our results support that the selective restoration of SMN expression in the spinal cord has a beneficial impact not only on αMNs but also on skeletal myofibers. However, the rescue of SMN expression in muscle appears to be necessary for the complete recovery of motor function.
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11
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Ramos DM, d’Ydewalle C, Gabbeta V, Dakka A, Klein SK, Norris DA, Matson J, Taylor SJ, Zaworski PG, Prior TW, Snyder PJ, Valdivia D, Hatem CL, Waters I, Gupte N, Swoboda KJ, Rigo F, Bennett CF, Naryshkin N, Paushkin S, Crawford TO, Sumner CJ. Age-dependent SMN expression in disease-relevant tissue and implications for SMA treatment. J Clin Invest 2019; 129:4817-4831. [PMID: 31589162 PMCID: PMC6819103 DOI: 10.1172/jci124120] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUNDSpinal muscular atrophy (SMA) is caused by deficient expression of survival motor neuron (SMN) protein. New SMN-enhancing therapeutics are associated with variable clinical benefits. Limited knowledge of baseline and drug-induced SMN levels in disease-relevant tissues hinders efforts to optimize these treatments.METHODSSMN mRNA and protein levels were quantified in human tissues isolated during expedited autopsies.RESULTSSMN protein expression varied broadly among prenatal control spinal cord samples, but was restricted at relatively low levels in controls and SMA patients after 3 months of life. A 2.3-fold perinatal decrease in median SMN protein levels was not paralleled by comparable changes in SMN mRNA. In tissues isolated from nusinersen-treated SMA patients, antisense oligonucleotide (ASO) concentration and full-length (exon 7 including) SMN2 (SMN2-FL) mRNA level increases were highest in lumbar and thoracic spinal cord. An increased number of cells showed SMN immunolabeling in spinal cord of treated patients, but was not associated with an increase in whole-tissue SMN protein levels.CONCLUSIONSA normally occurring perinatal decrease in whole-tissue SMN protein levels supports efforts to initiate SMN-inducing therapies as soon after birth as possible. Limited ASO distribution to rostral spinal and brain regions in some patients likely limits clinical response of motor units in these regions for those patients. These results have important implications for optimizing treatment of SMA patients and warrant further investigations to enhance bioavailability of intrathecally administered ASOs.FUNDINGSMA Foundation, SMART, NIH (R01-NS096770, R01-NS062869), Ionis Pharmaceuticals, and PTC Therapeutics. Biogen provided support for absolute real-time RT-PCR.
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Affiliation(s)
| | - Constantin d’Ydewalle
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Amal Dakka
- PTC Therapeutics, South Plainfield, New Jersey, USA
| | | | | | - John Matson
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | | | | | - Thomas W. Prior
- Center for Human Genetics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Pamela J. Snyder
- Department of Pathology, Ohio State University, Columbus, Ohio, USA
| | - David Valdivia
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christine L. Hatem
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ian Waters
- The Sidney Kimmel Comprehensive Cancer Center, Department of Oncology, and
| | - Nikhil Gupte
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kathryn J. Swoboda
- Center for Genomic Medicine, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | | | | | | | - Thomas O. Crawford
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Charlotte J. Sumner
- Department of Neuroscience and
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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12
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Delivery of GalNAc-Conjugated Splice-Switching ASOs to Non-hepatic Cells through Ectopic Expression of Asialoglycoprotein Receptor. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 16:313-325. [PMID: 30965276 PMCID: PMC6453860 DOI: 10.1016/j.omtn.2019.02.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 02/28/2019] [Accepted: 02/28/2019] [Indexed: 01/29/2023]
Abstract
Splice-switching antisense oligonucleotides (ASOs) are promising therapeutic tools to target various genetic diseases, including cancer. However, in vivo delivery of ASOs to orthotopic tumors in cancer mouse models or to certain target tissues remains challenging. A viable solution already in use is receptor-mediated uptake of ASOs via tissue-specific receptors. For example, the asialoglycoprotein receptor (ASGP-R) is exclusively expressed in hepatocytes. Triantennary N-acetylgalactosamine (GalNAc) (GN3)-conjugated ASOs bind to the receptor and are efficiently internalized by endocytosis, enhancing ASO potency in the liver. Here we explore the use of GalNAc-mediated targeting to deliver therapeutic splice-switching ASOs to cancer cells that ectopically express ASGP-R, both in vitro and in tumor mouse models. We found that ectopic expression of the major isoform ASGP-R1 H1a is sufficient to promote uptake and increase GN3-ASO potency to various degrees in four of five tested cancer cells. We show that cell-type-specific glycosylation of the receptor does not affect its activity. In vivo, GN3-conjugated ASOs specifically target subcutaneous xenograft tumors that ectopically express ASGP-R1, and modulate splicing significantly more strongly than unconjugated ASOs. Our work shows that GN3-targeting is a useful tool for proof-of-principle studies in orthotopic cancer models, until endogenous receptors are identified and exploited for efficiently targeting cancer cells.
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13
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Saini J, Faroni A, Abd Al Samid M, Reid AJ, Lightfoot AP, Mamchaoui K, Mouly V, Butler-Browne G, McPhee JS, Degens H, Al-Shanti N. Simplified in vitro engineering of neuromuscular junctions between rat embryonic motoneurons and immortalized human skeletal muscle cells. STEM CELLS AND CLONING-ADVANCES AND APPLICATIONS 2019; 12:1-9. [PMID: 30863121 PMCID: PMC6388735 DOI: 10.2147/sccaa.s187655] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Background Neuromuscular junctions (NMJs) consist of the presynaptic cholinergic motoneuron terminals and the corresponding postsynaptic motor endplates on skeletal muscle fibers. At the NMJ the action potential of the neuron leads, via release of acetylcholine, to muscle membrane depolarization that in turn is translated into muscle contraction and physical movement. Despite the fact that substantial NMJ research has been performed, the potential of in vivo NMJ investigations is inadequate and difficult to employ. A simple and reproducible in vitro NMJ model may provide a robust means to study the impact of neurotrophic factors, growth factors, and hormones on NMJ formation, structure, and function. Methods This report characterizes a novel in vitro NMJ model utilizing immortalized human skeletal muscle stem cells seeded on 35 mm glass-bottom dishes, cocultured and innervated with spinal cord explants from rat embryos at ED 13.5. The cocultures were fixed and stained on day 14 for analysis and assessment of NMJ formation and development. Results This unique serum- and trophic factor-free system permits the growth of cholinergic motoneurons, the formation of mature NMJs, and the development of highly differentiated contractile myotubes, which exhibit appropriate configuration of transversal triads, representative of in vivo conditions. Conclusion This coculture system provides a tool to study vital features of NMJ formation, regulation, maintenance, and repair, as well as a model platform to explore neuromuscular diseases and disorders affecting NMJs.
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Affiliation(s)
- Jasdeep Saini
- Musculoskeletal Science & Sports Medicine Research Centre, School of Healthcare Science, Manchester Metropolitan University, Manchester, UK,
| | - Alessandro Faroni
- Blond McIndoe Laboratories, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.,Department of Plastic Surgery & Burns, University Hospitals of South Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Marwah Abd Al Samid
- Musculoskeletal Science & Sports Medicine Research Centre, School of Healthcare Science, Manchester Metropolitan University, Manchester, UK,
| | - Adam J Reid
- Blond McIndoe Laboratories, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.,Department of Plastic Surgery & Burns, University Hospitals of South Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Adam P Lightfoot
- Musculoskeletal Science & Sports Medicine Research Centre, School of Healthcare Science, Manchester Metropolitan University, Manchester, UK,
| | - Kamel Mamchaoui
- Center for Research in Myology, Sorbonne Université- INSERM, Paris, France
| | - Vincent Mouly
- Center for Research in Myology, Sorbonne Université- INSERM, Paris, France
| | | | - Jamie S McPhee
- Department of Sport and Exercise Science, Manchester Metropolitan University, Manchester, UK
| | - Hans Degens
- Musculoskeletal Science & Sports Medicine Research Centre, School of Healthcare Science, Manchester Metropolitan University, Manchester, UK, .,Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania.,University of Medicine and Pharmacy of Targu Mures, Targu Mures, Romania
| | - Nasser Al-Shanti
- Musculoskeletal Science & Sports Medicine Research Centre, School of Healthcare Science, Manchester Metropolitan University, Manchester, UK,
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14
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Dominguez CE, Cunningham D, Chandler DS. SMN regulation in SMA and in response to stress: new paradigms and therapeutic possibilities. Hum Genet 2017; 136:1173-1191. [PMID: 28852871 PMCID: PMC6201753 DOI: 10.1007/s00439-017-1835-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/07/2017] [Indexed: 12/12/2022]
Abstract
Low levels of the survival of motor neuron (SMN) protein cause the neurodegenerative disease spinal muscular atrophy (SMA). SMA is a pediatric disease characterized by spinal motor neuron degeneration. SMA exhibits several levels of severity ranging from early antenatal fatality to only mild muscular weakness, and disease prognosis is related directly to the amount of functional SMN protein that a patient is able to express. Current therapies are being developed to increase the production of functional SMN protein; however, understanding the effect that natural stresses have on the production and function of SMN is of critical importance to ensuring that these therapies will have the greatest possible effect for patients. Research has shown that SMN, both on the mRNA and protein level, is highly affected by cellular stress. In this review we will summarize the research that highlights the roles of SMN in the disease process and the response of SMN to various environmental stresses.
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Affiliation(s)
- Catherine E Dominguez
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - David Cunningham
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Dawn S Chandler
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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15
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Farrar MA, Park SB, Vucic S, Carey KA, Turner BJ, Gillingwater TH, Swoboda KJ, Kiernan MC. Emerging therapies and challenges in spinal muscular atrophy. Ann Neurol 2017; 81:355-368. [PMID: 28026041 PMCID: PMC5396275 DOI: 10.1002/ana.24864] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 12/13/2016] [Accepted: 12/18/2016] [Indexed: 12/14/2022]
Abstract
Spinal muscular atrophy (SMA) is a hereditary neurodegenerative disease with severity ranging from progressive infantile paralysis and premature death (type I) to limited motor neuron loss and normal life expectancy (type IV). Without disease‐modifying therapies, the impact is profound for patients and their families. Improved understanding of the molecular basis of SMA, disease pathogenesis, natural history, and recognition of the impact of standardized care on outcomes has yielded progress toward the development of novel therapeutic strategies and are summarized. Therapeutic strategies in the pipeline are appraised, ranging from SMN1 gene replacement to modulation of SMN2 encoded transcripts, to neuroprotection, to an expanding repertoire of peripheral targets, including muscle. With the advent of preliminary trial data, it can be reasonably anticipated that the SMA treatment landscape will transform significantly. Advancement in presymptomatic diagnosis and screening programs will be critical, with pilot newborn screening studies underway to facilitate preclinical diagnosis. The development of disease‐modifying therapies will necessitate monitoring programs to determine the long‐term impact, careful evaluation of combined treatments, and further acceleration of improvements in supportive care. In advance of upcoming clinical trial results, we consider the challenges and controversies related to the implementation of novel therapies for all patients and set the scene as the field prepares to enter an era of novel therapies. Ann Neurol 2017;81:355–368
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Affiliation(s)
- Michelle A Farrar
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Susanna B Park
- Brain & Mind Centre and Sydney Medical School, University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital and Western Clinical School, University of Sydney, Sydney, Australia
| | - Kate A Carey
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Bradley J Turner
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburg, Edinburg, United Kingdom
| | - Kathryn J Swoboda
- Center for Human Genetics Research, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA
| | - Matthew C Kiernan
- Brain & Mind Centre and Sydney Medical School, University of Sydney, Sydney, Australia
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16
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Sahashi K, Katsuno M, Hung G, Adachi H, Kondo N, Nakatsuji H, Tohnai G, Iida M, Bennett CF, Sobue G. Silencing neuronal mutant androgen receptor in a mouse model of spinal and bulbar muscular atrophy. Hum Mol Genet 2015; 24:5985-94. [PMID: 26231218 DOI: 10.1093/hmg/ddv300] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/21/2015] [Indexed: 12/25/2022] Open
Abstract
Spinal and bulbar muscular atrophy (SBMA), an adult-onset neurodegenerative disease that affects males, results from a CAG triplet repeat/polyglutamine expansions in the androgen receptor (AR) gene. Patients develop progressive muscular weakness and atrophy, and no effective therapy is currently available. The tissue-specific pathogenesis, especially relative pathological contributions between degenerative motor neurons and muscles, remains inconclusive. Though peripheral pathology in skeletal muscle caused by toxic AR protein has been recently reported to play a pivotal role in the pathogenesis of SBMA using mouse models, the role of motor neuron degeneration in SBMA has not been rigorously investigated. Here, we exploited synthetic antisense oligonucleotides to inhibit the RNA levels of mutant AR in the central nervous system (CNS) and explore its therapeutic effects in our SBMA mouse model that harbors a mutant AR gene with 97 CAG expansions and characteristic SBMA-like neurogenic phenotypes. A single intracerebroventricular administration of the antisense oligonucleotides in the presymptomatic phase efficiently suppressed the mutant gene expression in the CNS, and delayed the onset and progression of motor dysfunction, improved body weight gain and survival with the amelioration of neuronal histopathology in motor units such as spinal motor neurons, neuromuscular junctions and skeletal muscle. These findings highlight the importance of the neurotoxicity of mutant AR protein in motor neurons as a therapeutic target.
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Affiliation(s)
- Kentaro Sahashi
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan,
| | - Gene Hung
- Isis Pharmaceuticals, Carlsbad, CA 92008, USA and
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environmental Health School of Medicine, Kitakyushu 807-8555, Japan
| | - Naohide Kondo
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Hideaki Nakatsuji
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Genki Tohnai
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Madoka Iida
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | | | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan,
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17
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Tsalikis J, Tattoli I, Ling A, Sorbara MT, Croitoru DO, Philpott DJ, Girardin SE. Intracellular Bacterial Pathogens Trigger the Formation of U Small Nuclear RNA Bodies (U Bodies) through Metabolic Stress Induction. J Biol Chem 2015; 290:20904-20918. [PMID: 26134566 DOI: 10.1074/jbc.m115.659466] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 12/30/2022] Open
Abstract
Invasive bacterial pathogens induce an amino acid starvation (AAS) response in infected host cells that controls host defense in part by promoting autophagy. However, whether AAS has additional significant effects on the host response to intracellular bacteria remains poorly characterized. Here we showed that Shigella, Salmonella, and Listeria interfere with spliceosomal U snRNA maturation in the cytosol. Bacterial infection resulted in the rerouting of U snRNAs and their cytoplasmic escort, the survival motor neuron (SMN) complex, to processing bodies, thus forming U snRNA bodies (U bodies). This process likely contributes to the decline in the cytosolic levels of U snRNAs and of the SMN complex proteins SMN and DDX20 that we observed in infected cells. U body formation was triggered by membrane damage in infected cells and was associated with the induction of metabolic stresses, such as AAS or endoplasmic reticulum stress. Mechanistically, targeting of U snRNAs to U bodies was regulated by translation initiation inhibition and the ATF4/ATF3 pathway, and U bodies rapidly disappeared upon removal of the stress, suggesting that their accumulation represented an adaptive response to metabolic stress. Importantly, this process likely contributed to shape the host response to invasive bacteria because down-regulation of DDX20 expression using short hairpin RNA (shRNA) amplified ATF3- and NF-κB-dependent signaling. Together, these results identify a critical role for metabolic stress and invasive bacterial pathogens in U body formation and suggest that this process contributes to host defense.
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Affiliation(s)
- Jessica Tsalikis
- Departments of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M6G 2T6, Canada
| | - Ivan Tattoli
- Departments of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M6G 2T6, Canada; Departments of Immunology, University of Toronto, Toronto M6G 2T6, Canada
| | - Arthur Ling
- Departments of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M6G 2T6, Canada
| | - Matthew T Sorbara
- Departments of Immunology, University of Toronto, Toronto M6G 2T6, Canada
| | - David O Croitoru
- Departments of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M6G 2T6, Canada
| | - Dana J Philpott
- Departments of Immunology, University of Toronto, Toronto M6G 2T6, Canada
| | - Stephen E Girardin
- Departments of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M6G 2T6, Canada.
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18
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Abstract
Precursor messenger RNA (pre-mRNA) splicing is a critical step in the posttranscriptional regulation of gene expression, providing significant expansion of the functional proteome of eukaryotic organisms with limited gene numbers. Split eukaryotic genes contain intervening sequences or introns disrupting protein-coding exons, and intron removal occurs by repeated assembly of a large and highly dynamic ribonucleoprotein complex termed the spliceosome, which is composed of five small nuclear ribonucleoprotein particles, U1, U2, U4/U6, and U5. Biochemical studies over the past 10 years have allowed the isolation as well as compositional, functional, and structural analysis of splicing complexes at distinct stages along the spliceosome cycle. The average human gene contains eight exons and seven introns, producing an average of three or more alternatively spliced mRNA isoforms. Recent high-throughput sequencing studies indicate that 100% of human genes produce at least two alternative mRNA isoforms. Mechanisms of alternative splicing include RNA-protein interactions of splicing factors with regulatory sites termed silencers or enhancers, RNA-RNA base-pairing interactions, or chromatin-based effects that can change or determine splicing patterns. Disease-causing mutations can often occur in splice sites near intron borders or in exonic or intronic RNA regulatory silencer or enhancer elements, as well as in genes that encode splicing factors. Together, these studies provide mechanistic insights into how spliceosome assembly, dynamics, and catalysis occur; how alternative splicing is regulated and evolves; and how splicing can be disrupted by cis- and trans-acting mutations leading to disease states. These findings make the spliceosome an attractive new target for small-molecule, antisense, and genome-editing therapeutic interventions.
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Affiliation(s)
- Yeon Lee
- Center for RNA Systems Biology; Division of Biochemistry, Biophysics, and Structural Biology; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204;
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19
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Staropoli JF, Li H, Chun SJ, Allaire N, Cullen P, Thai A, Fleet CM, Hua Y, Bennett CF, Krainer AR, Kerr D, McCampbell A, Rigo F, Carulli JP. Rescue of gene-expression changes in an induced mouse model of spinal muscular atrophy by an antisense oligonucleotide that promotes inclusion of SMN2 exon 7. Genomics 2015; 105:220-8. [PMID: 25645699 DOI: 10.1016/j.ygeno.2015.01.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/25/2015] [Indexed: 01/09/2023]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by disruption of the survival motor neuron 1 (SMN1) gene, partly compensated for by the paralogous gene SMN2. Exon 7 inclusion is critical for full-length SMN protein production and occurs at a much lower frequency for SMN2 than for SMN1. Antisense oligonucleotide (ASO)-mediated blockade of an intron 7 splicing silencer was previously shown to promote inclusion of SMN2 exon 7 in SMA mouse models and mediate phenotypic rescue. However, downstream molecular consequences of this ASO therapy have not been defined. Here we characterize the gene-expression changes that occur in an induced model of SMA and show substantial rescue of those changes in central nervous system tissue upon intracerebroventricular administration of an ASO that promotes inclusion of exon 7, with earlier administration promoting greater rescue. This study offers a robust reference set of preclinical pharmacodynamic gene expression effects for comparison of other investigational therapies for SMA.
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Affiliation(s)
- John F Staropoli
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Huo Li
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Seung J Chun
- Neuroscience Drug Discovery, Isis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Norm Allaire
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Patrick Cullen
- Neuroscience Drug Discovery, Isis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Alice Thai
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Christina M Fleet
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Yimin Hua
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - C Frank Bennett
- Neuroscience Drug Discovery, Isis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Doug Kerr
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Alexander McCampbell
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA
| | - Frank Rigo
- Neuroscience Drug Discovery, Isis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - John P Carulli
- Division of Genetics and Genomics, Biogen Idec, 12 Cambridge Center, Cambridge, MA 02142, USA.
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20
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Hua Y, Liu YH, Sahashi K, Rigo F, Bennett CF, Krainer AR. Motor neuron cell-nonautonomous rescue of spinal muscular atrophy phenotypes in mild and severe transgenic mouse models. Genes Dev 2015; 29:288-97. [PMID: 25583329 PMCID: PMC4318145 DOI: 10.1101/gad.256644.114] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Survival of motor neuron (SMN) deficiency causes spinal muscular atrophy (SMA), but restoring SMN in motor neurons only partially rescues SMA in mouse models. Hua et al. address the relative importance of SMN restoration in the CNS versus peripheral tissues in mouse models by using a therapeutic splice-switching antisense oligonucleotide to restore SMN and a complementary decoy oligonucleotide to neutralize its effects in the CNS. Increasing SMN exclusively in peripheral tissues completely rescued necrosis in mild SMA mice and robustly extended survival in severe SMA mice, with significant improvements in vulnerable tissues and motor function. Survival of motor neuron (SMN) deficiency causes spinal muscular atrophy (SMA), but the pathogenesis mechanisms remain elusive. Restoring SMN in motor neurons only partially rescues SMA in mouse models, although it is thought to be therapeutically essential. Here, we address the relative importance of SMN restoration in the central nervous system (CNS) versus peripheral tissues in mouse models using a therapeutic splice-switching antisense oligonucleotide to restore SMN and a complementary decoy oligonucleotide to neutralize its effects in the CNS. Increasing SMN exclusively in peripheral tissues completely rescued necrosis in mild SMA mice and robustly extended survival in severe SMA mice, with significant improvements in vulnerable tissues and motor function. Our data demonstrate a critical role of peripheral pathology in the mortality of SMA mice and indicate that peripheral SMN restoration compensates for its deficiency in the CNS and preserves motor neurons. Thus, SMA is not a cell-autonomous defect of motor neurons in SMA mice.
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Affiliation(s)
- Yimin Hua
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215021, China; Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
| | - Ying Hsiu Liu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Kentaro Sahashi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Frank Rigo
- Isis Pharmaceuticals, Carlsbad, California 92010, USA
| | | | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA;
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21
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Xiong HY, Alipanahi B, Lee LJ, Bretschneider H, Merico D, Yuen RKC, Hua Y, Gueroussov S, Najafabadi HS, Hughes TR, Morris Q, Barash Y, Krainer AR, Jojic N, Scherer SW, Blencowe BJ, Frey BJ. RNA splicing. The human splicing code reveals new insights into the genetic determinants of disease. Science 2015; 347:1254806. [PMID: 25525159 PMCID: PMC4362528 DOI: 10.1126/science.1254806] [Citation(s) in RCA: 775] [Impact Index Per Article: 86.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
To facilitate precision medicine and whole-genome annotation, we developed a machine-learning technique that scores how strongly genetic variants affect RNA splicing, whose alteration contributes to many diseases. Analysis of more than 650,000 intronic and exonic variants revealed widespread patterns of mutation-driven aberrant splicing. Intronic disease mutations that are more than 30 nucleotides from any splice site alter splicing nine times as often as common variants, and missense exonic disease mutations that have the least impact on protein function are five times as likely as others to alter splicing. We detected tens of thousands of disease-causing mutations, including those involved in cancers and spinal muscular atrophy. Examination of intronic and exonic variants found using whole-genome sequencing of individuals with autism revealed misspliced genes with neurodevelopmental phenotypes. Our approach provides evidence for causal variants and should enable new discoveries in precision medicine.
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Affiliation(s)
- Hui Y Xiong
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Babak Alipanahi
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Leo J Lee
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Hannes Bretschneider
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. Department of Computer Science, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Daniele Merico
- McLaughlin Centre, University of Toronto, Toronto, Ontario M5G 0A4, Canada. Centre for Applied Genomics, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ryan K C Yuen
- McLaughlin Centre, University of Toronto, Toronto, Ontario M5G 0A4, Canada. Centre for Applied Genomics, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Yimin Hua
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Serge Gueroussov
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Hamed S Najafabadi
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Timothy R Hughes
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Quaid Morris
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Yoseph Barash
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Nebojsa Jojic
- eScience Group, Microsoft Research, Redmond, WA 98052, USA
| | - Stephen W Scherer
- Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. McLaughlin Centre, University of Toronto, Toronto, Ontario M5G 0A4, Canada. Centre for Applied Genomics, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Benjamin J Blencowe
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. McLaughlin Centre, University of Toronto, Toronto, Ontario M5G 0A4, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Brendan J Frey
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada. Program on Genetic Networks and Program on Neural Computation & Adaptive Perception, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada. Department of Computer Science, University of Toronto, Toronto, Ontario M5S 3G4, Canada. McLaughlin Centre, University of Toronto, Toronto, Ontario M5G 0A4, Canada. Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada. eScience Group, Microsoft Research, Redmond, WA 98052, USA.
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22
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Lee Y, Rio DC. Mechanisms and Regulation of Alternative Pre-mRNA Splicing. Annu Rev Biochem 2015. [PMID: 25784052 DOI: 10.1146/annurev-biochem-060614-034316.mechanisms] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Precursor messenger RNA (pre-mRNA) splicing is a critical step in the posttranscriptional regulation of gene expression, providing significant expansion of the functional proteome of eukaryotic organisms with limited gene numbers. Split eukaryotic genes contain intervening sequences or introns disrupting protein-coding exons, and intron removal occurs by repeated assembly of a large and highly dynamic ribonucleoprotein complex termed the spliceosome, which is composed of five small nuclear ribonucleoprotein particles, U1, U2, U4/U6, and U5. Biochemical studies over the past 10 years have allowed the isolation as well as compositional, functional, and structural analysis of splicing complexes at distinct stages along the spliceosome cycle. The average human gene contains eight exons and seven introns, producing an average of three or more alternatively spliced mRNA isoforms. Recent high-throughput sequencing studies indicate that 100% of human genes produce at least two alternative mRNA isoforms. Mechanisms of alternative splicing include RNA-protein interactions of splicing factors with regulatory sites termed silencers or enhancers, RNA-RNA base-pairing interactions, or chromatin-based effects that can change or determine splicing patterns. Disease-causing mutations can often occur in splice sites near intron borders or in exonic or intronic RNA regulatory silencer or enhancer elements, as well as in genes that encode splicing factors. Together, these studies provide mechanistic insights into how spliceosome assembly, dynamics, and catalysis occur; how alternative splicing is regulated and evolves; and how splicing can be disrupted by cis- and trans-acting mutations leading to disease states. These findings make the spliceosome an attractive new target for small-molecule, antisense, and genome-editing therapeutic interventions.
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Affiliation(s)
- Yeon Lee
- Center for RNA Systems Biology; Division of Biochemistry, Biophysics, and Structural Biology; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204;
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A sensitive assay system to test antisense oligonucleotides for splice suppression therapy in the mouse liver. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e193. [PMID: 25226162 PMCID: PMC4222650 DOI: 10.1038/mtna.2014.44] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 07/30/2014] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated the efficacy of antisense therapy for splicing defects in cellular models of metabolic diseases, suppressing the use of cryptic splice sites or pseudoexon insertions. To date, no animal models with these defects are available. Here, we propose exon skipping of the phenylalanine hydroxylase (Pah) gene expressed in liver and kidney to generate systemic hyperphenylalaninemia in mice as a sensitive in vivo assay to test splice suppression. Systemic elevation of blood L-Phe can be quantified using tandem MS/MS. Exon 11 and/or 12 skipping for the normal PAH gene was validated in hepatoma cells for comparing two oligonucleotide chemistries, morpholinos and locked nucleic acids. Subsequently, Vivo-morpholinos (VMO) were tested in wild-type and in phenotypically normal Pahenu2/+ heterozygous mice to target exon 11 and/or 12 of the murine Pah gene using different VMO dosing, mode of injection and treatment regimes. Consecutive intravenous injections of VMO resulted in transient hyperphenylalaninemia correlating with complete exon skipping and absence of PAH protein and enzyme activity. Sustained effect required repeated injection of VMOs. Our results provide not only a sensitive in vivo assay to test for splice-modulating antisense oligonucleotides, but also a simple method to generate murine models for genetic liver diseases.
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Lee KY, Li M, Manchanda M, Batra R, Charizanis K, Mohan A, Warren SA, Chamberlain CM, Finn D, Hong H, Ashraf H, Kasahara H, Ranum LPW, Swanson MS. Compound loss of muscleblind-like function in myotonic dystrophy. EMBO Mol Med 2013; 5:1887-900. [PMID: 24293317 PMCID: PMC3914532 DOI: 10.1002/emmm.201303275] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/30/2013] [Accepted: 09/06/2013] [Indexed: 02/04/2023] Open
Abstract
Myotonic dystrophy (DM) is a multi-systemic disease that impacts cardiac and skeletal muscle as well as the central nervous system (CNS). DM is unusual because it is an RNA-mediated disorder due to the expression of toxic microsatellite expansion RNAs that alter the activities of RNA processing factors, including the muscleblind-like (MBNL) proteins. While these mutant RNAs inhibit MBNL1 splicing activity in heart and skeletal muscles, Mbnl1 knockout mice fail to recapitulate the full-range of DM symptoms in these tissues. Here, we generate mouse Mbnl compound knockouts to test the hypothesis that Mbnl2 functionally compensates for Mbnl1 loss. Although Mbnl1−/−; Mbnl2−/− double knockouts (DKOs) are embryonic lethal, Mbnl1−/−; Mbnl2+/− mice are viable but develop cardinal features of DM muscle disease including reduced lifespan, heart conduction block, severe myotonia and progressive skeletal muscle weakness. Mbnl2 protein levels are elevated in Mbnl1−/− knockouts where Mbnl2 targets Mbnl1-regulated exons. These findings support the hypothesis that compound loss of MBNL function is a critical event in DM pathogenesis and provide novel mouse models to investigate additional pathways disrupted in this RNA-mediated disease.
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Affiliation(s)
- Kuang-Yung Lee
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, USA; Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan
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25
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Sahashi K, Ling KKY, Hua Y, Wilkinson JE, Nomakuchi T, Rigo F, Hung G, Xu D, Jiang YP, Lin RZ, Ko CP, Bennett CF, Krainer AR. Pathological impact of SMN2 mis-splicing in adult SMA mice. EMBO Mol Med 2013; 5:1586-601. [PMID: 24014320 PMCID: PMC3799581 DOI: 10.1002/emmm.201302567] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 08/06/2013] [Accepted: 08/09/2013] [Indexed: 12/18/2022] Open
Abstract
Loss-of-function mutations in SMN1 cause spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. The related SMN2 gene expresses suboptimal levels of functional SMN protein, due to a splicing defect. Many SMA patients reach adulthood, and there is also adult-onset (type IV) SMA. There is currently no animal model for adult-onset SMA, and the tissue-specific pathogenesis of post-developmental SMN deficiency remains elusive. Here, we use an antisense oligonucleotide (ASO) to exacerbate SMN2 mis-splicing. Intracerebroventricular ASO injection in adult SMN2-transgenic mice phenocopies key aspects of adult-onset SMA, including delayed-onset motor dysfunction and relevant histopathological features. SMN2 mis-splicing increases during late-stage disease, likely accelerating disease progression. Systemic ASO injection in adult mice causes peripheral SMN2 mis-splicing and affects prognosis, eliciting marked liver and heart pathologies, with decreased IGF1 levels. ASO dose–response and time-course studies suggest that only moderate SMN levels are required in the adult central nervous system, and treatment with a splicing-correcting ASO shows a broad therapeutic time window. We describe distinctive pathological features of adult-onset and early-onset SMA.
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26
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The alternative heart: impact of alternative splicing in heart disease. J Cardiovasc Transl Res 2013; 6:945-55. [PMID: 23775418 DOI: 10.1007/s12265-013-9482-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/04/2013] [Indexed: 01/16/2023]
Abstract
Alternative splicing is the main driver of protein diversity and allows the production of different proteins from each gene in the genome. Changes in exon exclusion, intron retention or the use of alternative splice sites can alter protein structure, localisation, regulation and function. In the heart, alternative splicing of sarcomeric genes, ion channels and cell signalling proteins can lead to cardiomyopathies, arrhythmias and other pathologies. Also, a number of inherited conditions and heart-related diseases develop as a result of mutations affecting splicing. Here, we review the impact that changes in alternative splicing have on individual genes and on whole biological processes associated with heart disease. We also discuss promising therapeutic tools based on the manipulation of alternative splicing.
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Wirth B, Garbes L, Riessland M. How genetic modifiers influence the phenotype of spinal muscular atrophy and suggest future therapeutic approaches. Curr Opin Genet Dev 2013; 23:330-8. [PMID: 23602330 DOI: 10.1016/j.gde.2013.03.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/26/2013] [Accepted: 03/18/2013] [Indexed: 01/06/2023]
Abstract
Both complex disorders and monogenetic diseases are often modulated in their phenotype by further genetic, epigenetic or extrinsic factors. This gives rise to extensive phenotypic variability and potentially protection from disease manifestations, known as incomplete penetrance. Approaches including whole transcriptome, exome, genome, methylome or proteome analyses of highly discordant phenotypes in a few individuals harboring mutations at the same locus can help to identify these modifiers. This review describes the complexity of modifying factors of one of the most frequent autosomal recessively inherited disorders in humans, spinal muscular atrophy (SMA). We will outline how this knowledge contributes to understanding of the regulatory networks and molecular pathology of SMA and how this knowledge will influence future approaches to therapies.
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Affiliation(s)
- Brunhilde Wirth
- Institute of Human Genetics, Institute for Genetics, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
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28
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Schreml J, Riessland M, Paterno M, Garbes L, Roßbach K, Ackermann B, Krämer J, Somers E, Parson SH, Heller R, Berkessel A, Sterner-Kock A, Wirth B. Severe SMA mice show organ impairment that cannot be rescued by therapy with the HDACi JNJ-26481585. Eur J Hum Genet 2012; 21:643-52. [PMID: 23073311 DOI: 10.1038/ejhg.2012.222] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Spinal muscular atrophy (SMA) is the leading genetic cause of early childhood death worldwide and no therapy is available today. Many drugs, especially histone deacetylase inhibitors (HDACi), increase SMN levels. As all HDACi tested so far only mildly ameliorate the SMA phenotype or are unsuitable for use in humans, there is still need to identify more potent drugs. Here, we assessed the therapeutic power of the pan-HDACi JNJ-26481585 for SMA, which is currently used in various clinical cancer trials. When administered for 64 h at 100 nM, JNJ-26481585 upregulated SMN levels in SMA fibroblast cell lines, including those from non-responders to valproic acid. Oral treatment of Taiwanese SMA mice and control littermates starting at P0 showed no overt extension of lifespan, despite mild improvements in motor abilities and weight progression. Many treated and untreated animals showed a very rapid decline or unexpected sudden death. We performed exploratory autopsy and histological assessment at different disease stages and found consistent abnormalities in the intestine, heart and lung and skeletal muscle vasculature of SMA animals, which were not prevented by JNJ-26481585 treatment. Interestingly, some of these features may be only indirectly caused by α-motoneuron function loss but may be major life-limiting factors in the course of disease. A better understanding of - primary or secondary - non-neuromuscular organ involvement in SMA patients may improve standard of care and may lead to reassessment of how to investigate SMA patients clinically.
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Affiliation(s)
- Julia Schreml
- Institute of Human Genetics, University of Cologne, Cologne, Germany
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